A facile functionalized routine for the synthesis of side-chain sulfonated poly(arylene ether ketone sulfone) as proton exchange membranes

A series of side-chain type proton exchange membrane (PEM) based on sulfonated poly(arylene ether ketone sulfone) (S-SPAEKS) has been synthesized through a simple free radical reaction by grafting 2-acrylamido-2-methyl propane sulfonic acid (AMPS) onto the polymer main chain. The side-chain type membranes showed lower water absorption and swelling ratio than that of main-chain type membranes. S-SPAEKS-2 exhibited the highest proton conductivity of 0.095 S cm−1 at 80 °C, while its swelling ratio was only 7.09% at the same temperature. Much lower methanol permeability in the range of 1.27 × 10−8 cm2 s−1–2.61 × 10−7 cm2 s−1 compared to Nafion 117 (1.55 × 10−6 cm2 s−1) were also observed for the prepared membranes. Moreover, hydrophilic/hydrophobic phase separation morphology is observed obviously from TEM images. The results indicate that the side-chain type S-SPAEKS membranes are good alternative PEM materials for fuel cells.